I've been doing a bunch of research on the whole TPI to ZZ4-TPI swap.
This is what I came up with so far:
1.Take a ZZ4 shorblock and re-use all the parts of the 305/350(oil pan, timing chain, etc.)
2. Use a set of aftermarket heads and cam.I looked in the AFR catalog and they have 3 different types of heads that are "emissions legal" and are made to go on a L98(180cc,190cc and 195cc)
I intend on using Edlebrock intake w/SLP runners and a larger TB.
I would like some sugestions as far as heads/cam combo. I'm looking to make high RPM power since I have 4.10s so the AFRs 195cc heads look atractive since they make power between 2000-6500rpm.
So please, guys, give me some head/cam combos to work with the above mentioned ZZ4 project. I'm hoping to achieve 350-380hp and 400 or so lbs/f of torque. Correct me if I'm wrong about anything I wrote. I do need to keep this emissions legal.
Thanks in advance
PS. I know that there's an EGR issue to consider. Someone has mentioned that it could be bypassed via new the new prom(which I will aquire in turn) and a way to "run plumming" to quote somebody else. I would appreiate some detailed help in this area.



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1990 Formula
Factory:TPI-305/Dual Cat(230hp),5 Speed,3.42 rear.
Dealer instaled:Aluminum Drive Shaft
Mods:SLP air foil,K&N Filter, Accel:wires,coil cap,rotor.Hypertech Thermomaster chip,Stat,Fan switch,TES headers,MSD6AL,AFPR(50), Harwood fiberglass hood.
Flowmaster 3" Cat-back exhaust,TB coolant bypass,B&M Ripper shifter, Centerforce dual friction clutch, Ported & Siamesed Plenum matched to SLP Runners, March Power/Amp Pulleys, Richmond 4.10 gears. (???HP)

 

Oh yeah. I want to thank in advance all those who might suggest transmission and rear end beef-ups but it's not nessasary. I'm aware of T5s and 7.5 rear's faults/weakness'.
Mike

 

The way I ran the EGR was to use an intake manifold that would accept the Corvette style EGR tube. The manifold is made by TPIS. They can give you the specific parts and the advice. It requires that you use some smog legal headers and weld a fitting to the headers that connects to the tube.

 

For high RPM power (5000+ RPM), you'll need to ax the TPI setup and buy a Miniram (much better with your 4.10's and five speed). Then buy a cam with 220+ duration and 0.5 lift to go with some AFR 190's.

As it stands, the long tube runner setup you are building on paper would be grossly unbalanced. If you want to stay the LTR route (it does look good), buy some AFR 190's and the LT4 HOT cam from GM, and keep the 3.42's.

Hope this helps.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

Sorry, the miniram may still not be emissions legal, so that pretty much leaves the superram.

 

I have the EGR blocked off but if you get the shortblock and use AFR heads you can get heads with EGR ports and then you have no issue.

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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,ZEX nitrous,Walbro 255lph f-pump,Accel AFPR,Random Technology catback,!cats,and mutch more.

 

Thanks to all you fellas for answers to the EGR problem. I really appreciate it.
As far as getting rid of the TPI, I think that you can get a TPI to "breathe".
My TPI will have a ported/siamesed base mated to fully ported/siamesed SLP runners mated to a ported/siamesed plenum,that is ported in turn to a larger TB.
I think that this combo will be enough to come close to MR and SR. Anyway, I don't want to buy a whole new "Top"to my future 350.Those set-ups cost as much as a decent ThirdGen car.

 

I just thought of something. According to all the suggestions and all the archived posts I've read, many people want a ZZ4 and they want use a TPI-type set-up yet keeping it street/emissions legal.Most of the posts end with no conclusive answer, and many people buy the ZZ4 Longblock.
In my humble opinion, I think that there should be a Tech-Article outlining how you can get a new 350 in your 3rdGen.
Why not get a ZZ4 Shortblock. Than buy some AFR(or simmilar) heads that are meant for a a sniffer legal L98.Also get an Edlebrock or Accel base with whatever cam you can get away with.Have a chip burned and you're good to go(for the most part). It appears that you have to switch some stuff from your old 305/350 TPI to either a Short or Longblock ZZ4.Like the water pump, distributor, timing chain, etc.
I beleive that the going with the Shortblock is more economical, no matter if you're doing it yourself or having a shop do it. Keep in mind, I mean a sniffer legal TPI/ZZ4 set-up. There is a price difference of about $1400 between a 355hp ZZ4 Longblock and a Shortblock version.
Let me know if I'm on the wrong track in any of my comments.
Thanks


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1990 Formula
Factory:TPI-305/Dual Cat(230hp),5 Speed,3.42 rear.
Dealer instaled:Aluminum Drive Shaft
Mods:SLP air foil,K&N Filter, Accel:wires,coil cap,rotor.Hypertech Thermomaster chip,Stat,Fan switch,TES headers,MSD6AL,AFPR(50), Harwood fiberglass hood.
Flowmaster 3" Cat-back exhaust,TB coolant bypass,B&M Ripper shifter, Centerforce dual friction clutch, Ported & Siamesed Plenum matched to SLP Runners w/Edlebrock Base, March Power/Amp Pulleys, Richmond 4.10 gears,265/50/16 BFGoodrich rear tires.

 

I think you are correct, if I had it to do over again I think I would get the short block AFR heads and a HOT cam. But I don't think you will save any money. If you are going to go to all the trouble to get good solid high output motor don't reuse old parts get a new water pump, new chain and at least rebuild your distributer. Then worry about a solid rebuild on your trans. and how long your 10bolt is going to last. It is not cheap but when you compair it to any thing on the road for the money it is still a great deal.

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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,ZEX nitrous,Walbro 255lph f-pump,Accel AFPR,Random Technology catback,!cats,and mutch more.

 

I agree with you as far as thoughing on a new timing chain ad some oher goodies. It makes good practice to get new stuff since you got the motor apart and outside the car. But not all people have the ready cash to start buying new water pumps and timng chain sets or distribtors. In many of the posts I've read, there were a lot of guys who just wanted to swap from and high millege 350s and 305 TPIs to a new block and possibly re-use as much from the old engine as possible to save costs. It all adds up, you know.
What meant by "Economical" was not only in terms of dollars. I've read a lot of posts(research) as far as TPI/ZZ4/Emissions legal swap and asked some questions. Many people, like myself, just wanted a new, economical 350 to go under their TPI and/or TPI-type EFI set-ups.
What I figured out was that on the ZZ4 Long-block(meant for a carb and no emissions) you have a lot of parts that you can't use for a TPI set-up; Waterpump, distributor, intake manifold.
The heads are also non-EGR type.
So by "most economical",I meant both money-wice as well as practical-wice in terms of Sniffer Legal. Saving time trying to figure out how to turn a ZZ4 Long-block into a Sniffer Legal TPI motor seems to be the biggest question(according to my readings). Since the above mentioned ZZ4 was meant to be a carbed motor, it's kinda self defeating to try to retrofit the sucker to EFI.
So all things considered, the ZZ4 Short-block is the most viable and economical(financially and intelectually) option for a 305/350 TPI swap to a fresh new Street Legal 350TPI engine.
Am I wrong? PLMK.



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1990 Formula
Factory:TPI-305/Dual Cat(230hp),5 Speed,3.42 rear.
Dealer instaled:Aluminum Drive Shaft
Mods:SLP air foil,K&N Filter, Accel:wires,coil cap,rotor.Hypertech Thermomaster chip,Stat,Fan switch,TES headers,MSD6AL,AFPR(50), Harwood fiberglass hood.
Flowmaster 3" Cat-back exhaust,TB coolant bypass,B&M Ripper shifter, Centerforce dual friction clutch, Ported & Siamesed Plenum matched to SLP Runners w/Edlebrock Base, March Power/Amp Pulleys, Richmond 4.10 gears,265/50/16 BFGoodrich rear tires.